Buggy code:
public class Tree extends Composite { NSTableColumn firstColumn ; NSTableColumn checkColumn ; NSTableHeaderView headerView ; TreeItem [ ] items ; int itemCount ; TreeColumn [ ] columns ; TreeColumn sortColumn ; int columnCount ; int sortDirection ; float levelIndent ; boolean ignoreExpand ; boolean ignoreSelect ; public Tree ( Composite parent , int style ) { } void _addListener ( int eventType , Listener listener ) { } TreeItem _getItem ( TreeItem parentItem , int index ) { } public void addSelectionListener ( SelectionListener listener ) { } public void addTreeListener ( TreeListener listener ) { } boolean checkData ( TreeItem item , boolean redraw ) { } static int checkStyle ( int style ) { } protected void checkSubclass ( ) { } void clear ( TreeItem parentItem , int index , boolean all ) { } void clearAll ( TreeItem parentItem , boolean all ) { } public void clear ( int index , boolean all ) { } public void clearAll ( boolean all ) { } public Point computeSize ( int wHint , int hHint , boolean changed ) { } void createHandle ( ) { <START_BUG> SWTScrollView scrollWidget = ( ( SWTScrollView ) ( new SWTScrollView ( ) . alloc ( ) ) ) ; <END_BUG> scrollWidget . initWithFrame ( new NSRect ( ) ) ; scrollWidget . setHasHorizontalScroller ( true ) ; scrollWidget . setHasVerticalScroller ( true ) ; scrollWidget . setAutohidesScrollers ( true ) ; scrollWidget . setBorderType ( ( hasBorder ( ) ? OS . NSBezelBorder : OS . NSNoBorder ) ) ; NSOutlineView widget = ( ( NSOutlineView ) ( new SWTOutlineView ( ) . alloc ( ) ) ) ; widget . initWithFrame ( new NSRect ( ) ) ; widget . setAllowsMultipleSelection ( ( ( ( style ) & ( SWT . MULTI ) ) != 0 ) ) ; widget . setAutoresizesOutlineColumn ( false ) ; widget . setAutosaveExpandedItems ( true ) ; widget . setDataSource ( widget ) ; widget . setDelegate ( widget ) ; widget . setDoubleAction ( sel_sendDoubleSelection ) ; if ( ! ( hasBorder ( ) ) ) widget . setFocusRingType ( NSFocusRingTypeNone ) ; headerView = widget . headerView ( ) ; headerView . retain ( ) ; widget . setHeaderView ( null ) ; NSString str = NSString . stringWith ( "" ) ; if ( ( ( style ) & ( SWT . CHECK ) ) != 0 ) { checkColumn = ( ( NSTableColumn ) ( new NSTableColumn ( ) . alloc ( ) ) ) ; checkColumn . initWithIdentifier ( str ) ; checkColumn . headerCell ( ) . setTitle ( str ) ; widget . addTableColumn ( checkColumn ) ; widget . setOutlineTableColumn ( checkColumn ) ; NSButtonCell cell = ( ( NSButtonCell ) ( new NSButtonCell ( ) . alloc ( ) . init ( ) ) ) ; checkColumn . setDataCell ( cell ) ; cell . setButtonType ( NSSwitchButton ) ; cell . setImagePosition ( NSImageOnly ) ; cell . setAllowsMixedState ( true ) ; checkColumn . setWidth ( getCheckColumnWidth ( ) ) ; checkColumn . setResizingMask ( NSTableColumnNoResizing ) ; checkColumn . setEditable ( false ) ; cell . release ( ) ; } firstColumn = ( ( NSTableColumn ) ( new NSTableColumn ( ) . alloc ( ) ) ) ; firstColumn . initWithIdentifier ( str ) ; firstColumn . headerCell ( ) . setTitle ( str ) ; widget . addTableColumn ( firstColumn ) ; widget . setOutlineTableColumn ( firstColumn ) ; NSBrowserCell cell = ( ( NSBrowserCell ) ( new NSBrowserCell ( ) . alloc ( ) . init ( ) ) ) ; cell . setLeaf ( true ) ; firstColumn . setDataCell ( cell ) ; cell . release ( ) ; levelIndent = widget . indentationPerLevel ( ) ; scrollView = scrollWidget ; view = widget ; } void createItem ( TreeColumn column , int index ) { } void createItem ( TreeItem item , TreeItem parentItem , int index ) { } void createWidget ( ) { } Color defaultBackground ( ) { } Color defaultForeground ( ) { } public void deselectAll ( ) { } public void deselect ( TreeItem item ) { } void destroyItem ( TreeColumn column ) { } void destroyItem ( TreeItem item ) { } void fixScrollBar ( ) { } int getCheckColumnWidth ( ) { } public TreeColumn getColumn ( int index ) { } public int getColumnCount ( ) { } public int [ ] getColumnOrder ( ) { } public TreeColumn [ ] getColumns ( ) { } public int getGridLineWidth ( ) { } public int getHeaderHeight ( ) { } public boolean getHeaderVisible ( ) { } int getInsetWidth ( ) { } public TreeItem getItem ( int index ) { } public TreeItem getItem ( Point point ) { } public int getItemCount ( ) { } public int getItemHeight ( ) { } public TreeItem [ ] getItems ( ) { } public boolean getLinesVisible ( ) { } public TreeItem getParentItem ( ) { } public TreeItem [ ] getSelection ( ) { } public int getSelectionCount ( ) { } public TreeColumn getSortColumn ( ) { } public int getSortDirection ( ) { } public TreeItem getTopItem ( ) { } public int indexOf ( TreeColumn column ) { } public int indexOf ( TreeItem item ) { } int outlineView_child_ofItem ( int outlineView , int index , int ref ) { } int outlineView_objectValueForTableColumn_byItem ( int outlineView , int tableColumn , int ref ) { } boolean outlineView_isItemExpandable ( int outlineView , int ref ) { } int outlineView_numberOfChildrenOfItem ( int outlineView , int ref ) { } void outlineView_willDisplayCell_forTableColumn_item ( int outlineView , int cell , int tableColumn , int ref ) { } void outlineViewSelectionDidChange ( int notification ) { } boolean outlineView_shouldCollapseItem ( int outlineView , int ref ) { }

Fix:
NSScrollView scrollWidget = ( ( NSScrollView ) ( new SWTScrollView ( ) . alloc ( ) ) ) ;